Week Numbers for the Year 1999
Knowing the week numbers for 1999 can be helpful for planning events, managing projects, or simply staying organized. Here’s a complete breakdown of all the weeks in 1999, including their start and end dates.
What Are Week Numbers?
Week numbers are a standardized way of counting the weeks in a year. Each week is assigned a number from 1 to 52 (sometimes 53), depending on how the calendar aligns with the start of the year. According to the ISO 8601 standard, each week starts on a Monday, and Week 1 is the week that contains the first Thursday of the year.
Week Number Table for 1999
| Week Number | Start Date | End Date |
|---|---|---|
| Week 1 | Jan 4, 1999 | Jan 10, 1999 |
| Week 2 | Jan 11, 1999 | Jan 17, 1999 |
| Week 3 | Jan 18, 1999 | Jan 24, 1999 |
| Week 4 | Jan 25, 1999 | Jan 31, 1999 |
| Week 5 | Feb 1, 1999 | Feb 7, 1999 |
| Week 6 | Feb 8, 1999 | Feb 14, 1999 |
| Week 7 | Feb 15, 1999 | Feb 21, 1999 |
| Week 8 | Feb 22, 1999 | Feb 28, 1999 |
| Week 9 | Mar 1, 1999 | Mar 7, 1999 |
| Week 10 | Mar 8, 1999 | Mar 14, 1999 |
| Week 11 | Mar 15, 1999 | Mar 21, 1999 |
| Week 12 | Mar 22, 1999 | Mar 28, 1999 |
| Week 13 | Mar 29, 1999 | Apr 4, 1999 |
| Week 14 | Apr 5, 1999 | Apr 11, 1999 |
| Week 15 | Apr 12, 1999 | Apr 18, 1999 |
| Week 16 | Apr 19, 1999 | Apr 25, 1999 |
| Week 17 | Apr 26, 1999 | May 2, 1999 |
| Week 18 | May 3, 1999 | May 9, 1999 |
| Week 19 | May 10, 1999 | May 16, 1999 |
| Week 20 | May 17, 1999 | May 23, 1999 |
| Week 21 | May 24, 1999 | May 30, 1999 |
| Week 22 | May 31, 1999 | Jun 6, 1999 |
| Week 23 | Jun 7, 1999 | Jun 13, 1999 |
| Week 24 | Jun 14, 1999 | Jun 20, 1999 |
| Week 25 | Jun 21, 1999 | Jun 27, 1999 |
| Week 26 | Jun 28, 1999 | Jul 4, 1999 |
| Week 27 | Jul 5, 1999 | Jul 11, 1999 |
| Week 28 | Jul 12, 1999 | Jul 18, 1999 |
| Week 29 | Jul 19, 1999 | Jul 25, 1999 |
| Week 30 | Jul 26, 1999 | Aug 1, 1999 |
| Week 31 | Aug 2, 1999 | Aug 8, 1999 |
| Week 32 | Aug 9, 1999 | Aug 15, 1999 |
| Week 33 | Aug 16, 1999 | Aug 22, 1999 |
| Week 34 | Aug 23, 1999 | Aug 29, 1999 |
| Week 35 | Aug 30, 1999 | Sep 5, 1999 |
| Week 36 | Sep 6, 1999 | Sep 12, 1999 |
| Week 37 | Sep 13, 1999 | Sep 19, 1999 |
| Week 38 | Sep 20, 1999 | Sep 26, 1999 |
| Week 39 | Sep 27, 1999 | Oct 3, 1999 |
| Week 40 | Oct 4, 1999 | Oct 10, 1999 |
| Week 41 | Oct 11, 1999 | Oct 17, 1999 |
| Week 42 | Oct 18, 1999 | Oct 24, 1999 |
| Week 43 | Oct 25, 1999 | Oct 31, 1999 |
| Week 44 | Nov 1, 1999 | Nov 7, 1999 |
| Week 45 | Nov 8, 1999 | Nov 14, 1999 |
| Week 46 | Nov 15, 1999 | Nov 21, 1999 |
| Week 47 | Nov 22, 1999 | Nov 28, 1999 |
| Week 48 | Nov 29, 1999 | Dec 5, 1999 |
| Week 49 | Dec 6, 1999 | Dec 12, 1999 |
| Week 50 | Dec 13, 1999 | Dec 19, 1999 |
| Week 51 | Dec 20, 1999 | Dec 26, 1999 |
| Week 52 | Dec 27, 1999 | Jan 2, 2000 |
| Week 53 | Jan 3, 2000 | Jan 9, 2000 |
Yes, 1999 has 53 weeks! This happens when the year starts on a Thursday or is a leap year that ends on a Thursday—allowing for that extra ISO week.
Why Are Week Numbers Useful?
Week numbers are used in a variety of scenarios across professional and personal settings:
- Software Development: Sprint planning and agile iterations often use weekly cycles.
- Business Operations: Sales goals, reporting cycles, and payroll often reference week numbers.
- Education: Academic calendars may follow weekly structures, particularly in Europe.
- Travel & Hospitality: Hotels, airlines, and tour companies often plan based on week-based pricing and schedules.
Fun Fact
The ISO 8601 week-numbering system was first introduced in 1988 and is used by many countries around the world, especially in Europe. The U.S. doesn't commonly use it, but many global systems rely on it for consistency.
Find the Week Number of Any Date
Want to know the week number of a specific date? In PHP, you can use the DateTime object like this:
Week number is: 16
List the week numbers of the coming years.